1. Field of the Invention
The present invention relates generally to an electronic musical instrument of the type which computes a waveshape through utilization of a discrete Fourier transfer, and more particularly to an electronic musical insturment which is adapted to repeat (or cut back) a high foot tone in a high sound range.
2. Description of the Prior Art
It is said that electronic musical instruments, especially electronic organs have been developed as a substitute for true organs. As a result of this, even at present, a tone channel called tibia or flute and a draw bar (hamond type) have different pitches or feet for the same tone. High foot tones, for example, 2, 1 3/5, 15/8, and 1 feet sounds (the foot being indicated by a numeral with a prime in the accompanying drawings), have very high musical frequencies in a high sound range. At high musical frequencies, a sense of volume disappears rapidly as is well known from the Fletcher-Munson curve. In addition, the circuit for producing high musical frequencies is large-scale and requires a high clock frequency, and hence it is very disadvantageous economically.
To avoid the abovesaid defect, it is necessary to increase the sense of volume in the high sound range for high foot tones and to eliminate the necessity of the high clock frequency. It is considered that this could be achieved by repeating or cutting back a musical sound in the high sound range. In conventional electronic musical instruments, however, when a key switch for a sound range in which to cut back a musical sound is closed, a musical note of the corresponding interval in a lower sound range is selected. Hence the key switch mechanism is complex in arrangement and control system and low in reliability, and allows easy mixing of noise because of complex wiring.